丹溪谓夏月炎暑盛行，人身内外皆热，其说甚的。乃张景岳谓，夏月伏阴，人
身外热内寒，冬至伏阳，人身外寒内热。以夏至阴生，地上热而井水寒，冬至阳生，
地上寒而井水温为证。其说似是而非。乃知有天时，而不知有地理者也。人身之气，
与天地通，固从天时而变，亦随地势而移。既有东西南北之殊，岂无上下高深之别。
人之身固在地上也，非在地中也。设夏时而身处井中，则不特内寒，即外亦寒矣。
尚得如其说谓外热内寒耶？然则置身地上，不特外热，即内亦热，自可反观而见矣。
试观浮瓜沉李，咽水饮冰，未尝畏冷，其情可见。冬月能如是乎？或曰∶
夏月汗多，汗多则亡阳，阳亡则阴生于内，谓之伏阴，非欤？曰∶夏月汗多，是人
皆然，岂皆亡阳乎？不过虚其津液耳。津液虚即阴虚，阴虚则阳愈炽，观小便之短
而赤可知。不滋金水，而补火土，吾见其惑也。曰∶古人于暑证，多用热剂，非欤？
曰∶此因证转虚寒乃然，不可一概混施也。问∶夏月阳气外泄，冬月阳气五内，非
欤？曰∶阳外泄则汗出而内涸，故清润之品为宜；气内敛则化水而阴滋，故温热之
剂可任。观夏月渴而小便短赤，冬月不渴而小便清长，则阳外泄者之内非冷，阳内
藏者之中非热，不辨自明矣。
朱丹溪认为，夏季炎热酷暑盛行，人体内外都是热的，这种说法非常确切。然而张景岳却认为，夏季体内潜伏着阴寒之气，人体外部热而内部寒；冬至时体内潜伏着阳气，人体外部寒而内部热。他以夏至时节阴气开始生长，地面热而井水寒；冬至时节阳气开始生长，地面寒而井水温作为证据。他的说法看似有理实则错误，这是只知天时变化，而不知地理环境差异的缘故。
人体的气机与天地相通，固然随天时而变化，也随地势而移动。既然有东西南北地域的差异，难道没有上下高深的区别吗？人的身体确实位于地面上，并非位于地底下。假如在夏季身处井中，那么不仅内部寒冷，外部也会寒冷。这还能像他所说的那样是外热内寒吗？既然如此，置身于地面上，不仅外部热，内部也是热的，这通过反观即可明白。试看夏天将瓜果浮于水面、沉于水中（冰镇），吞咽凉水、饮用冰块，人们并不觉得冷，其中的情理由此可见。冬天能这样做吗？
有人问：夏季出汗多，出汗多则导致阳气亡失，阳气亡失则阴气生于内部，这就叫作“伏阴”，不是吗？回答说：夏季出汗多是所有人都有的现象，难道都导致阳气亡失吗？不过是使津液亏虚罢了。津液亏虚就是阴虚，阴虚则阳气更加炽盛，从小便短少且颜色赤红就可以知道。如果不滋补肺金和肾水，反而去补益心火和脾土，我认为是迷惑不解的。
又问：古人在治疗暑证时，多用温热性质的药物，不是吗？回答说：这是因为病情转化为虚寒证时才这样，不能一概而论混用。
再问：夏季阳气向外发泄，冬季阳气向内收敛，不是吗？回答说：阳气向外发泄则汗出而内部枯竭，所以适宜使用清凉滋润的药物；阳气向内收敛则化为水液而使阴气滋生，所以可以使用温热的药剂。观察夏天口渴且小便短赤，冬天不口渴且小便清长，就知道阳气向外发泄的人内部并非寒冷，阳气向内收藏的人内部并非炎热，这一点不辨自明。
Zhu Danxi stated that during summer, when intense heat prevails, the human body is hot both internally and externally; this view is quite accurate. However, Zhang Jingyue argued that in summer, Yin-cold lies hidden within the body, resulting in external heat and internal cold; whereas at the Winter Solstice, Yang-heat lies hidden within, resulting in external cold and internal heat. He used as evidence the phenomenon that at the Summer Solstice, Yin begins to generate, making the ground hot but well water cold; and at the Winter Solstice, Yang begins to generate, making the ground cold but well water warm. His argument seems plausible but is actually incorrect, as it acknowledges the changes of celestial timing (Tianshi) while ignoring geographical conditions (Dili).
The Qi of the human body connects with Heaven and Earth; it indeed changes according to celestial timing but also shifts according to geographical terrain. Just as there are differences among East, West, South, and North, how can there be no distinctions between high/low or deep/shallow? The human body resides on the surface of the earth, not underground. If one were situated inside a well during summer, not only would the interior be cold, but the exterior would also be cold. Could one still claim, as he did, that it is externally hot and internally cold? Conversely, being situated on the ground, not only is the exterior hot, but the interior is also hot, which can be deduced by reflection. Consider the practice of floating melons and sinking plums (in water), swallowing cold water, and drinking ice without feeling cold; the principle is evident from this. Can one do the same in winter?
One might ask: In summer, sweating is profuse; profuse sweating leads to the loss of Yang-Qi (Yang Qi), and the loss of Yang leads to the generation of Yin within, which is called "hidden Yin" (Fu Yin), is it not? I reply: Profuse sweating in summer occurs in everyone, yet does it always lead to the loss of Yang? It merely depletes the Body Fluids (Jinye). Depletion of Body Fluids constitutes Yin Deficiency (Yin Xu); Yin deficiency causes Yang to become even more blazing, which can be observed through short and red urine. If one fails to nourish Lung Metal and Kidney Water, but instead tonifies Heart Fire and Spleen Earth, I consider this to be confused.
Another question arises: Did ancients often use hot-natured agents for treating Heatstroke (Shu Zheng), is it not so? I reply: This is done only when the condition transforms into deficiency-cold; one cannot indiscriminately apply such methods.
Further inquiry: In summer, Yang Qi leaks outward; in winter, Yang Qi gathers inward, is this correct? I reply: When Yang Qi leaks outward, sweat is produced and the interior becomes dry/depleted, thus cooling and moistening agents are appropriate; when Qi gathers inward, it transforms into fluids and nourishes Yin, thus warm and hot agents can be employed. Observing that in summer one feels thirsty with short, red urine, while in winter one feels no thirst with clear, long urine, it becomes self-evident that those whose Yang leaks outward do not have a cold interior, and those whose Yang gathers inward do not have a hot interior.